(CNN) -- Passengers who disembarked from a Carnival Cruise Lines ship that was towed to port after losing power earlier this week gave mixed reviews on the experience, with several declaring it "an adventure."

"A lot of things went wrong, but it was really fun," said one small passenger, Ryan Harlan, who was traveling with his parents. "We went to the Kids' Camp."

He said the Kids' Camp was, in fact, his favorite part, because he made some friends.

And the worst part? "Being stranded in the middle of the ocean," he said.

Some 3,300 passengers left the ship Thursday after the three-day ordeal that began with a fire in the ship's engine room Monday. Engineers were unable to restore power to the ship after the fire was extinguished, leaving passengers without air conditioning, hot showers or decent meals. Instead, they had to settle for Spam and Pop-Tarts dropped off by the USS Ronald Reagan, a U.S. Navy aircraft carrier that came to assist.

The National Transportation Safety Board said Thursday it was investigating the onboard fire.

Passengers said they were not told there was a fire. Guest Marquis Horace said the cruise line told passengers there was "a flameless fire. ... Everybody just laughed." And passenger Ken King said guests were told there was "a lot of smoke."

"It was absolutely deplorable," Horace said. At one point, the ship ran out of food, he said, and "they started making mayo sandwiches."

"I expected a really nice time and it was like Gilligan's Island or something," he said.

He said he ate a lot of bananas and dry cereal, but at one point didn't want to eat anymore because the smell of overflowing toilets, spoiled food and rotten milk was overwhelming.

Once the USS Ronald Reagan showed up to assist, passengers felt safer, he said. And the Navy provided good food -- Horace said he particularly enjoyed the bean burritos.

"We tried to make the best of it," said Horace, who was traveling with his best friend for both of their birthdays. "It just completely got ruined."

Some of the elderly passengers on board particularly struggled, he said. One woman, who used a scooter, could not take the stairs, and other passengers had to help her and carry the scooter. Horace said the woman across the hall from him was a diabetic, and her insulin had to be kept cold, but there was no way to do that. He said he and his companion had to help her to the bathroom. At one point, "she was crying because she had no food," he said.

One passenger was wheeled off the Splendor on a stretcher and was taken to a waiting ambulance, CNN affiliate KGTV reported.

Horace said passengers brushed their teeth with bottled water, and "showering in the dark is not fun."

"All that stuff we take for granted was totally missed," Horace said.

He told CNN affiliate KFMB some of the floors were "saturated with feces and urine" after the toilets backed up. "It was really nasty," he said.

Trying to navigate the ship in the dark was "like a search and rescue mission," said passenger Josh Vest, who was on his honeymoon.

One woman, who said she worked for the cruise line, was wearing a T-shirt that said, "I survived the 2010 Carnival Cruise Spamcation." Vendors met passengers at the port, selling the shirts for $20.

"The first part of it was OK," King said of the cruise. "The food was great, staff was great." But after the fire, he said, the food "actually got worse. The toilets didn't work for about 12 hours."

Chris Harlan, Ryan's father, agreed. "The first night was great when we got aboard, dancing and all that stuff," he told CNN affiliate KUSI. "We called it an early night, and the next morning you could just feel the ship rattling, and we looked out the window and we could see smoke from our balcony."

Several people said the experience was "an adventure."

"Everything, from the military, to cold water showers, to Spam, to salads every day," Chris Harlan told CNN. Several passengers described long lines for food.

But "Carnival did a great job with the resources they had," he said. "I can't say enough. The crew was great. ... We just made the most of it."

The vessel became stranded Monday off the coast of Mexico after the fire.

While Carnival said Wednesday that most passengers knew that the Splendor's crew was doing the best it could, there were reports of passengers pledging not to take up the company's offer of a free replacement trip.

Because the ship was without most of its power, the company decided to wait until daylight Thursday for tugboats to deliver the Splendor to a dock, Carnival Cruise Lines CEO Gerry Cahill said at a news conference.

One passenger, David Zambrano, a KUSA-TV employee, called his Denver, Colorado, station Wednesday from his cell phone and said many passengers were in the dark in their cabins and had to wait in line for two hours to eat the cold meals, which were being delivered to the ship by helicopter from the USS Ronald Reagan.

"Many of the people I have talked to said that they will never take another cruise again, especially with Carnival," said Zambrano. Others, however, said they would return.

In addition to offering a free cruise, Carnival has promised passengers a refund and said it will cover their transportation costs.

"Conditions on the ship have been challenging," said Cahill, reiterating the cruise line's apologies to families.

"We're disappointed about it. Reports from the ship show guests believe we are doing the best we can," Cahill said. "We ruined their vacations. I am optimistic they will return."

Cahill said the crew did the best it could to make passengers comfortable, including offering free drinks.

"We wish to thank our guests for their patience and cooperation during this very difficult situation and offer our sincerest apologies," said Cahill.

"We know that the conditions were challenging and our crew worked extremely hard to make our guests as comfortable as possible until we could return them home safely. We sincerely apologize," de la Cruz said.

The USS Ronald Reagan resupplied the ship on Tuesday. Sailors stood on the deck in 50-yard lines, handing off boxes of water, frozen bread, sandwich meats, granola bars, paper plates and more for the Splendor. The Reagan received 60,000 pounds of food, bottled water and supplies by airlift for the cruise ship, said Cmdr. Greg Hicks, spokesman of the U.S. Third Fleet.

Carnival said it was making hotel and flight arrangements for guests once they reach port. About 100 representatives greeted the ship at the port Thursday to help passengers with transportation, hotel and other needs, Cahill said.

The fire occurred about 6 a.m. Monday in the engine room of the Splendor, the cruise line said in a statement on its website. The blaze was extinguished, and no passengers or crew were injured.

The seven-day cruise along the Mexican coast departed Sunday from Long Beach, California. Carnival has canceled a seven-day cruise that was to leave November 14 from Long Beach, the company said.

"We've been in business for 35 years," Cahill said. "We've never had anything like this happen before."

John Heald, Carnival's senior cruise director, blogged Wednesday from the Carnival Splendor. "I have to say that the crew has been absolutely epic and I am so very proud of each and every one of them," he wrote.